1, additive commutative law: Two numbers are added to exchange the position of addend, and the sum is unchanged.

2. Additive associative law: A+B = B+A.

3. Multiplicative commutative law: a× b = b× a.

4. Multiplicative associative law: a × b × c = a ×(b × c).

5. Multiplicative distribution law: a× b+a× c = a× b+c.

6. The nature of division: a ÷ b ÷ c = a ÷(b × c).

7. Nature of division: In division, the dividend and divisor are expanded (or reduced) by the same multiple at the same time, and the quotient remains unchanged. O is divided by any number that is not O. Simple multiplication: the multiplicand and the end of the multiplier are multiplied by O. You can multiply 1 before o first, and zero does not participate in the operation, and add a few zeros at the end of the product.

8. Division with remainder: dividend = quotient × divisor+remainder.